Diagnosing fever by touch: observational studyBMJ 1998; 317 doi: https://doi.org/10.1136/bmj.317.7154.321 (Published 01 August 1998) Cite this as: BMJ 1998;317:321
- Katherine Whybrew, medical student,
- Matthew Murray, medical student,
- Colin Morley, honorary consultant paediatrician. ()
- University of Cambridge, Department of Paediatrics, Box 226 Neonatal Intensive Care Unit, Addenbrooke's Hospital, Cambridge CB2 2QQ
- Correspondence to: Dr Morley
- Accepted 2 February 1998
Fever is a useful indicator of whether a child is seriously ill.1 Many mothers and doctors estimate children's temperature by touch.2 We assessed whether mothers and medical students could use touch to determine if children had fever.
Subjects, methods, and results
During their elective in a Zambian hospital, medical students and the child's mother felt children's abdomen, forehead, and neck and independently recorded whether the child felt hot. Simultaneously, a mercury thermometer was used to measure axillary temperature for exactly 3 minutes. Rectal temperature measurement was not permitted at this hospital.
In total, 1090 children aged 1 month to 16 years (median 2 years) were studied. The mean ambient temperature was 24.5 (SD 2.0)½C; the mean axillary temperature from 24 children not recently vaccinated and with no complaint was 36.7 (2SD 1.12)½C. Therefore 37.8½C or higher was defined as a fever. With this definition, 236 (27%) children had fever.
The mothers assessed 862 children and thought 574 (67%) were warm or hot. Their sensitivity was 94% (221/236), specificity 44% (273/626), positive predictive value 39% (221/574), and negative predictive value 95% (273/288).
Two students assessed 1086 children and thought 525 (48%) were warm or hot. Their sensitivity was 94% (257/274), specificity 67%(544/812), positive predictive value 49% (257/525), and negative predictive value 97% (544/561). Two students, working independently, had remarkably similar results (sensitivities 95% and 94%, positive predictive values 50% and 47%). The table shows the data for the two groups.
This study showed that when mothers and medical students felt the children they rarely missed a child with fever, but they overestimated the number who had fever.
Because it was impractical to measure rectal temperature for cultural reasons, axillary temperature had to be used. Axillary temperature is not always accurate. One study comparing axillary and rectal temperature found means of 36.8½C and 37.4½C, respectively, and a median difference of 0.5½C (range −>1.0½C to 3.2½C).3 The difference was largest in children with high fever. The shortcomings of axillary temperature measurement might have influenced our results: positive predictive values might have been higher if rectal temperature been used.
These children felt warmer than did children in Britain, possibly because of the higher ambient temperature and the tendency to overdress. Therefore, rather than use a range derived from a different population, we calculated a normal range for the group. Defining fever as a temperature of 37.8½C or more was higher than the temperature used in other studies (37.2½C,337.4½C,4 and 37.5½C5). In our study the thermometer was assiduously kept in the axilla for 3 minutes. In other studies the temperature was taken for a shorter time, which may account for the lower temperatures used.
A recent African study investigated the ability of patients (1606 men and children) or their carers to decide whether they had a fever.5Twenty per cent had fever, but only 28% of those thought to have fever did; of those thought to have a normal temperature, 92% did.
These two studies establish that, as a screening procedure, touch will seriously overestimate the incidence of fever, but with touch, fever will rarely be missed; also, a patient who does not feel hot is very likely not to have fever. A child who feels hot needs to have a temperature taken before fever is diagnosed.
Thanks to the parents and children who took part in the study and the helpful staff of Chikankata Hospital, Zambia.
Contributors: KW and MM collected the data and were closely involved in data analysis and presentation. CM suggested the project, helped with data analysis and presentation, and is guarantor for the paper.
Funding: Financial assistance from the Commonwealth Foundation; Churchill College, Cambridge; Pembroke College, Cambridge; Medical Defence Union; Lady Valerie France; John Zeal.
Conflict of interest: None.